VISUAL TOPOGRAPHY IN PRIMATE V2 - MULTIPLE REPRESENTATION ACROSS FUNCTIONAL STRIPES

The second visual cortical area (V2) of the primate is composed of rep eating thin, pale, and thick cytochrome oxidase stripes containing pri marily color-selective, broadband oriented, and disparity-selective ce lls, respectively, We have now examined topography in V2 with respect to these functional subdivisions, Our data suggest that there are mult iple, interleaved visual maps in V2, one for each of the color, orient ation, and disparity domains. The same region of Visual space is re-re presented by each stripe within a stripe cycle, resulting in discontin uities or ''jumps back'' in representation at stripe borders. Adjacent stripe cycles represent adjacent regions of space such that the visua l map is continuous from one stripe to the next like stripe. Receptive field size and scatter are significantly larger for thin stripes than for thick stripes, Unexpectedly, our data suggest two types of pale s tripes within each stripe cycle, one with scatter similar to thin stri pes and another to thick stripes. Some evidence also suggests the pres ence of multiple maps within individual stripes in V2. Consistent with functional clustering within single stripes (Ts'o et al., 1990b), we have recorded re-representations and topographic discontinuities coinc ident with functional borders within single stripes. These results sug gest that multiple and interleaved mapping may be a common organizatio nal strategy for representing multiple functional domains within a sin gle cortical area.